Chau, Marian , Reyes, Whitney , Ranker, Tom .
A field-based model of ecological factors influencing growth of the endangered Hawaiian fern Marsilea villosa and implications for conservation management.
Conserving endangered plant species is a complex task, and on-the-ground management is often trial and error, with managers doing their best to address immediate needs. Botanists can improve this process by conducting sound science upon which to base management practices. Marsilea villosa is an endangered endemic Hawaiian fern with seven remaining populations in ephemerally flooding drylands. Among its uncommon traits are long-lived sporocarps (i.e. highly modified leaves containing sporangia and spores), a requirement of flood and drought to complete its sexual life cycle, and extensive vegetative growth. We conducted a three-year field study on the ecology of M. villosa to identify factors with the greatest impact on its growth. We found that maximum flooding depth and canopy cover had strong positive relationships with M. villosa growth, and that all plots with over a 50% threshold of either variable reached 100% cover of M. villosa by the end of the study. Interaction effects explained the nuances of these relationships and confirmed some degree of synergy between the two variables. Percent cover of non-native understory species by functional groups (grasses and non-grass species) each had negative relationships with % cover of M. villosa, but interactions showed that % cover of non-grass species was driven by particular species over time, and that time since flooding had a greater influence on M. villosa growth than % cover of grasses. We recommend several specific management strategies that will optimize in situ conservation, guide reintroduction practices to promote self-sustaining new populations, and reduce the need for labor-intensive management.
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1 - University Of Hawaii, Department Of Botany, 3190 Maile Way, HONOLULU, HI, 96822-2279, USA
2 - National Science Foundation, Division Of Environmental Biology, 4201 Wilson Blvd, Room 635N, Arlington, VA, 22230, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Union E/Hyatt
Date: Monday, July 9th, 2012
Time: 9:15 AM